The present invention generally relates to the manufacture of tires for automobiles. More particularly, it relates to a method for pressure-adhering a joint portion of a tire building component material, and an apparatus used therefor.
In the manufacture of radial tires for automobiles, the tire building process includes a first stage wherein an inner liner and a ply carcass are wound onto a cylindrical drum, a bead member is fixed to each end of the ply carcass by bending the end of the ply carcass to wrap up the bead member to build a first cover, and sidewalls and the like are later adhered thereto, and a second stage wherein the first cover is formed into a toroidal shape, followed by adhering a breaker reinforcement layer, a tread and the like onto the outer periphery of the first cover.
The present invention is directed to a method for pressure-adhering edge portions of tire building component materials such as sidewalls in the first stage of the tire building process, and to an apparatus used therefor. More specifically, is the present invention is directed to such a method capable of dispensing with the skill of a pressure-adhering operator, eliminating the burden imposed on the operator and reducing the operation time period required by pressure-adhering joint portions of tire building material with the use of an apparatus separate from a tire building apparatus, and to the apparatus used therefor.
In the production process for rubber products such as tires and belts, in general, it is necessary to join together rubber component materials reinforced with fibers or the like such as carcass, belt, sidewall, inner liner and bead. This joining step needs to be performed quickly and assuredly for improving the quality of a tire or belt.
FIGS. 4 to 8 illustrate a conventional method of pressure-adhering a joint portion of a sidewall in a tire building process. This conventional pressure-adhering method is summarized in brief as follows:
(1) adhering sidewalls to a first cover (refer to FIG. 4); PA1 (2) cutting each sidewall automatically or manually (refer to FIG. 5); PA1 (3) mating the cut end portions of each sidewall with each other to form the joint portion (refer to FIG. 6); PA1 (4) pressure-adhering the joint portion completely with the use of a pressing roller or the like (refer to FIG. 7); and PA1 (5) enfolding the bead portion of each sidewall and entirely pressure-adhering each sidewall to the first cover (refer to FIG. 8). PA1 (1) adhering sidewalls to a first cover; PA1 (2) cutting each of the sidewalls at a given portion thereof; PA1 (3) provisionally securing a joint portion defined by the cut ends of each of the sidewalls; PA1 (4) enfolding a bead portion with a bead edge of the sidewall and entirely pressure-adhering each sidewall to the first cover; and PA1 (5) pressure-adhering the joint portion provisionally or initially with a machine, wherein the step (5) is carried out separately from a production line in which the steps (1) to (4) are carried out.
After the above procedure has been completed, the first cover is removed from the drum and then fed to the subsequent step.
In the step of pressure-adhering the joint portion of each sidewall as shown in FIG. 7, the joint portion 91 must be strongly compressed with a hand-operated roller 90 and completely crushed. This operation requires the skill and burden of an operator. Further, the tire building apparatus must be stopped during this operation and hence cannot be utilized effectively. Apparatus for automatically performing such pressure-adhering operation are disclosed in, for example, Japanese Unexamined Patent Publication No. 35709/1977 and Japanese Examined Patent Publication No. 106847/1981. Although these apparatuses do not require the skill and burden of an operator, they have a pressing roller mounted on the tire building apparatus and, hence, the apparatus must be stopped during the pressure-adhering operation. This unavoidably results in losses in the tire building process. Further, the apparatus demand fine adjustments depending on the kind of tire building component and hence cannot be simplified.
The present invention has been attained to overcome the foregoing problems. It is, therefore, an object of the present invention to provide a pressure-adhering method which can dispense with the skill of an operator, relieve the operator of burden and eliminate the losses in the tire building process, and an apparatus used therefor.